Photocomposing apparatus and method for varying character magnification

ABSTRACT

This disclosure depicts apparatus and method for selectively varying character magnification during photocomposition. Photocomposing apparatus is shown as including means for displaying a character to be recorded and a plurality of lenses of different focal length mounted upon a rotatable lens turret. Novel turret indexing means is disclosed as comprising turret monitoring means for determining coarsely when a selected one of the lenses is approaching an axis along which the characters are projected, switch means actuated by cam means on the turret for determining when the selected lens is substantially on the projection axis, and extremely accurate turret locking means which is responsive to inputs from the turret-monitoring means and the switch means for locking the turret with the selected lens located precisely on the projection axis.

United States Patent [72] Inventor James A. Tidd Haverhill, Mass. [21]Appl. No. 43,765 [22] Filed June 5, 1970 [45] Patented Jan.4, 1972 [73]Assignee Graphic Systems Incorporated Lowell, Mass.

[54] PHOTOCOMPOSING APPARATUS AND METHOD FOR VARYING CHARACTERMAGNIFICATION 11 Claims, 2 Drawing Figs.

[52] US. Cl 95/4.5, 95/45 [51] Int. Cl B4lb 13/10 [50] Field of Search95/4.5, 45;

[56] References Cited UNITED STATES PATENTS 2,898,829 8/1959 Wirtz etal. 95/4.5 3,486,429 12/1969 Morisawa... 95/4.5 3,487,761 l/1970 La Rue353/101 X Assistant ExaminerRichard L. Moses AttorneyRosen andSteinhilper ABSTRACT: This disclosure depicts apparatus and method forselectively varying character magnification during photocomposition.Photocomposing apparatus is shown as including means for displaying acharacter to be recorded and a plurality of lenses of different focallength mounted upon a rotatable lens turret. Novel turret indexing meansis disclosed as comprising turret monitoring means for determiningcoarsely when a selected one of the lenses is approaching an axis alongwhich the characters are projected, switch means actuated by cam meanson the turret for determining when the selected lens is substantially onthe projection axis, and extremely accurate turret locking means whichis responsive toinputs from the turret-monitoring means and the switchmeans for locking the turret with the selected lens located precisely onthe projection axis.

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LOGIC LOGIC PATENTEDJAN 41972 3.631775 sum 1 or 2 COMB.

LOGIC SEQUENTIA LOGIC Fig. l.

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READER j INVliN'I'OR JAMES A. TIDD ROSEN & STEINHILPER ATTORNEYSPATENTEU JAN 412272 SHEET 2 BF 2 INVENTOR JAMES A. TIDD RQSEN '82SIEINHILEER ATTORNEYS PIIOTOCOMPOSING APPARATUS AND METHOD FOR VARYINGCHARACTER MAGNIFICATION BACKGROUND OF THE INVENTION For manyapplications the capability of a photocomposing system to vary themagnification of the recorded characters is essential. In the past, thisexpedient has been achieved either by manual interchange of projectionlenses of different focal length, or by automatic interchange of lenseswith complex and relatively costly structures.

There has been recognized a very great need for a photocomposing systemwhich has the requisite high performance, yet which is priced withinreach of the thousands of medium and small-sized printing operations. Tobe of optimum usefulness in such printing operations, such low costapparatus must have a variable character magnification capability.

OBJECTS OF THE INVENTION It is an object of this invention to meet theabove-stated needs in photocomposing systems with apparatus providingfor the selection of different character magnifications over a widerange of magnificationvalues, and yet which is of low cost anduncompromised performance.

To this end, it is an object to provide apparatus in a photocom'posingmachine for varying character magnification including novel means forindexing a lens turret, which utilizes a unique combination of low-costcomponents cooperating in a novel way to give the said high performance.

Further objects and advantages of the invention will in part be obviousand will in part become apparent as the following description proceeds.

The features of novelty which characterize the invention will be pointedout with particularity in the claims annexed to and forming a part ofthis specification.

' BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of theinvention, reference may be had to the following detailed descriptiontaken in connection with the accompanying drawings wherein:

FIG. 1 is a partially schematic perspective view of apparatusimplementing the principles of this invention; and

FIG. 2 is a perspective view of the apparatus shown in FIG. 1 taken froma different viewpoint and showing in more detail character displaymeans.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings illustratephotocomposing apparatus implementing the principles of this inventionwhich, as stated above, involve novel means and methods for preciselyindexing a lens turret carrying a plurality of lenses of different focallength for providing a range of selectable character magnifications.

The drawings illustrate a portion of a photocomposing machine accordingto a preferred embodiment of the invention, including generally, acharacter display device in which a selected character isflash-illuminated, an optical projection system 11 for projecting animage of the selected character, and a flexible fiber optic bundle 12for transferring the projected character image to a recording station(not shown).

The character display device 10 is illustrated as comprising a characterdisplay drum l5 rotatably mounted on an axle 16. The drum 15 istransparent and may be constructed from materials such as glass orcertain of the transparent plastic materials. On the periphery of thedrum [5 is formed a channel 17 which received film strips 21 acting ascharacter storage members.

The sides of the channel 17 are defined by a pair of accurately machinedflanges 19, 20.

Positioned around the circumference of the drum l5 and associated withthe film strip receiving channel 17 are a plurality of fasteners 22, 24adapted to penetrate holes 23 in the ends of the film strips 21. Thefasteners have threads 25 for engaging the hub 36. Insert holes 26 inthe drum 1'5 permit finger access to the fasteners 22, 24.

A light source 28 and a photocell 30, arranged on opposite sides of thedrum l5, cooperate with a row of timing lines 45 on the film strips 21to generate a train of pulses useful in monitoring the locations of arow of alphanumeric characters 44 on the film strips 21. The lightsource 28 is mounted within the character display drum 15 and positionedbehind film strip receiving channel 17. The light source 28 is shown asbeing mounted on a support member 29 secured to the frame of themachine. The photocell 30 is mounted on a support 31 opposite lightsource 28.

A stroboscopic flash lamp 33 is positioned within the character displaydrum l5 and mounted on a suitable support 34 also secured to the frameof the machine. The lamp 33 is capable of being flashed for an extremelyshort duration, suchas, for example, a few microseconds.

The entire drum assembly, consisting of the character display drum l5and members mounted thereon is rotatably mounted on the axle 16. This isaccomplished for example, by means of a hub 36 mounted on bar 37 whichmay be connected, for example with a rotatable sleeve 38. At the lowerend of the sleeve 38 is a pulley 39 operatively driven by a drive memberor belt 40 which, in turn, is operatively mounted to be driven by pulley41 on a drive motor (not shown).

The optical projection system, generally designated 11, is illustratedin both FIGS. 1 and 2, but is perhaps more readily understood in theenlarged simplified presentation in FIG. 2. This optical projectionsystem includes a lens support in the form of a turret 46 comprising aplate 47 which is rotatably mounted on a shaft 48.

A plurality of projection lenses 54 is mounted on turret 46, each lensbeing of a different effective focal length and each being positioned soas to project an image at a predetermined magnification from the filmstrip 21 along a projection axis 50 to a fixed input end 55 of fiberoptic bundle 12.

In accordance with this invention, low-cost but high-performance meansare provided for accurately indexing the turret 46 upon command so as toposition a selected one of the plurality of lenses precisely on theprojection axis 50. To this end, there is provided low-costturret-monitoring means for coarsely determining when a selected one ofthe lenses 54 is approaching the projection axis, and inexpensiveswitching means for determining when the selected lens is substantiallyon the projection axis. The outputs from the turret-monitoring means andthe switching means are fed to an electronic control circuit whichefi'ects energization of a turret drive motor and actuates aninexpensive but very accurate locking device to lock the turret 46 withthe selected lens precisely on the projection axis 50.

Referring now to the drawings, the structures performing theabove-described functions in the illustrated embodiment will bediscussed. In the illustrated embodiment the turret 46 is driven by amotor 60 through a pair of speed-reducing spur gears 62, 64.

The motor is preferably a relatively small, slow speed AC motor of theunidirectional friction drive type which are readily availablecommercially at very modest prices.

The turret monitoring means is shown as taking the form of a rotaryswitch 66 driven at the same rate as the turret 46 by the motor 60through a spur gear 67 meshed with the spur gear 64 on the turret shaft48. The switch 66 is here shown as a l0-position switch corresponding inthe number of switch terminals to the number of lenses 54 carried by theturret 46. In accordance with this invention, the rotary switch 66 needhave very little accuracy and is therefore obtainable commercially atrelatively low cost. Lead 68 connects the rotary switch 66 to acombination logic circuit 70 which acts to control the operation of theturret-indexing system. The function of the-combinational logic circuit70 will be described in detail hereinafter.

The means for determining when the selected lens is on the opticalprojection axis is shown as taking the form of a microswitch 72. Theswitch 72 need have only moderate accuracy and may be of any of avariety of types which are available commercially at low cost. Themicroswitch 72 has a spring-biased plunger 74 carrying on the endthereof a rotatably mounted wheel 76. The outer periphery of the turretplate 47 has conical recesses 78 machined therein with high positionalaccuracy, one being located on each of the radials on which the lenses54 are located. The recesses 78 serve as accurate angular referencepoints for the lenses 54.

The lens turret 46 is shown as carrying ten lenses arranged indiametrically opposed pairs. The number of lenses which may be employedis arbitrary. The microswitch plunger 74 is precisely located on thediametrically opposite sides of the turret rotational axis from theoptical projection axis. Thus, when the wheel 76 on the microswitchplunger 74, acting as a cam follower, descends into a recess 78 in theplate 47, the microswitch 72 is actuated to indicate that a projectionlens 54 on the opposed side of the turret 46 from the microswitch 72 islocated substantially on the optical projection axis 50. A lead 80 fromthe microswitch 72 supplies the described turret position information tothe combinational logic circuit 70.

In order to lock the turret 46 securely in place with extreme positionalaccuracy when the selected lens 54 has been indicated to be located onthe optical projection axis, a low-cost locking device 84 is provided.The locking device 84 is positioned accurately with respect to saidprojection axis 50. The locking device 84 is shown as taking the form ofa solenoid 86 having a plunger 88 biased outwardly by a coil spring 90.The plunger 88 is shown as having a head 92, which may be composed ofDelrin (TM) or the like, having an accurately determined male conicalconfiguration which mates with the conical recesses 78 on the peripheryof the turret 46. A switch 94 actuated by movement of the plunger 88 isshown schematically as comprising a pair of contacts 96, 98 connected ina motor energization circuit 100. The motor energization circuit 100includes a source of AC power, here shown schematically as a generator102.

The operation of the system is as follows. A series of characters to beset in type are fed into the system in binary code on a perforated papertape 104. Alternatively, the character information may be supplied froma keyboard. The tape 104 is shown as being read by a tape reader 106.The coded character information is fed from the reader 106 to asequential logic circuit 108. One of the functions performed by thelogic circuit 108 is to decode a signal from the tape 104 whichindicates the magnification of the characters. This signal is fed to thecombinational logic circuit 70 which compares the coded signalindicating desired magnification with a code indicating themagnification of the lens 54 presently on the optical projection axis.If the information does not correspond, that is, if a different lens isneeded, the circuit 70 supplies an energization signal to the solenoid86 causing the plunger 88 to retract, thereby releasing the turret 46and closing the switch 94 in the motor energization circuit 100. Themotor 60 is thus energized, causing the lens turret 46 to rotate.Simultaneously therewith the wiping contact in the rotary switch 66 iscaused to rotate. The combinational logic circuit 70 contains well-knowncomparing circuits which compare the sequentially derived signals fromthe rotary switch 66 with the coded magnification signal received fromthe sequential logic circuit 108. The combinational logic circuit 70also perfonns an AND function as will become evident from the ensuingdescription. When the selected lens 54 is next approaching the opticalprojection axis, as indicated by a correspondence of the signal from therotary switch 66 with the coded magnification signal derived from thesequential logic circuit 108 and the microswitch 72 signals the locationof the selected lens substantially on the projection axis 50, thecombinational logic circuit 70 deenergizes the locking device 84.Deenergization of the locking device 84 causes the coil spring 90 tothrust the plunger 88 into the recess 78 radially registered with theselected lens 54 to thereby lock the selected lens precisely on theprojection axis. The projection of the plunger 88 into the recess 78opens the switch 94 to inactivate the turret drive motor 60.

Throughout this specification and in the claims appended hereto, theswitch 72 has been described as signaling when a lens 54 is locatedsubstantially on the optical projection axis. This description should beconstrued to allow for a small lead time since, in practice, theactuation of the plunger 88 is preferably caused to slightly lead theposition of the turret 46, that is to say, the locking device 84 isdeenergized slightly before the selected lens 54 is on the projectionaxis. This provision eliminates the possibility that the turret 46,which is preferably driven unidirectionally, might overrun the indexposition. The mating conical configuration of the plunger 88 andrecesses 78 performs an extremely precise positioning function anddetermines the accuracy of the turret position when locked at an indexlocation.

It is seen then that by this invention a unique combination ofcommercially abundant, low-cost components cooperate in structure andfunction to provide a low cost, yet extremely accurate turret-indexingsystem for a photocomposing machine.

Certain changes may be made in the above-described apparatus and methodwithout departing from the true spirit and scope of the invention hereininvolved. For example, means other than the motor 60 may be employed todrive the turret 46. The lens support may be a translatable carriagerather than a rotatable turret. The turret monitoring means need not bea rotary switch as described, but may take other forrns'consistent withits requisite function of coarsely monitoring the turret position. Themeans for signaling the location of the selected lens substantially onthe projection axis need not take the form of a microswitch sensing thelocation of conical recesses in the turret periphery which cooperatealso in the turret-locking function. Other arrangements are within thepurview of this invention. It is therefore intended that the abovedepiction shall be interpreted as being illustrative, and not in' alimiting sense.

What is claimed is:

1. ln photocomposing apparatus, the combination comprismg:

means for establishing a character to be recorded;

a lens support carrying a plurality of lenses in spaced rela tionship;means mounting said lens support for movement such that said lenses aresuccessively brought into position on an optical projection axis whensaid support is moved; and

lens support indexing means for moving said lens support to successivelylocate different ones of said plurality of lenses on said projectionaxis, comprising: motive means for moving said lens support, monitoringmeans for monitoring the position of said lens support to detenninecoarsely when a selected one of said plurality of lenses is approachingsaid projection axis,

electrical sensing means responsive to movement of said lens support fordetennining when said selected lens is located substantially on saidprojection axis,

electrically operable highly accurate mechanical locking means forlocking said lens support, and

control means responsive to said monitoring means and to said sensingmeans for actuating said locking means when said selected lens issubstantially on said projection axis, said locking means upon actuationvery precisely fixing the position of said selected lens on said axis.

2. ln photocomposing apparatus, the combination comprismg:

means for establishing a character to be recorded;

a lens turret carrying a plurality of lenses in angularly spacedrelationship;

means mounting said turret for rotation such that said lenses aresuccessively brought into position on an optical projection axis whensaid turret is rotated; and

turret indexing means for rotating said turret to selectively locatedifferent ones of said plurality of lenses on said projection axis,comprising: motive means for rotating said turret,

monitoring means for monitoring the angular position of said turret todetermine coarsely when a selected one of said plurality of lenses isapproaching said projection axis,

electrical sensing means responsive to movement of said turret fordetermining when said selected lens is located substantially on saidprojection axis,

electrically operable highly accurate mechanical locking means forlocking said turret, said locking means being positioned accurately withrespect to said axis, and

control means responsive to said monitoring means and to said sensingmeans for actuating said locking means when said selected lens issubstantially on said projection axis, said locking means upon actuationvery precisely fixing the position of said selected lens on said axis.

3. The apparatus defined by claim 2 wherein said turret defines aplurality of recesses angularly spaced thereon and wherein said lockingmeans includes a solenoid having a plunger adapted to enter one of saidrecesses to lock said turret when said solenoid is energized.

4. The apparatus defined by claim 3 wherein each of said recesses has afemale conical configuration and wherein said plunger has a tip with amale conical configuration mating with said female conical configurationof said recesses.

5. The apparatus defined by claim 2 wherein said turret includes aplurality of sharply defined angularly spaced cam means, and whereinsaid sensing means comprises a switch having an actuator following saidcam means.

6. The apparatus defined by claim 3 wherein said sensing means comprisesa switch having an actuator positioned to sense said recesses in saidturret.

7. The apparatus defined by claim 6 wherein said monitoring meanscomprises a rotary switch operatively coupled to said motive means anddriven thereby in synchronism with said turret.

8. In a photocomposing machine, the combination comprismg:

means for displaying a character to be recorded;

means for forming a real image of said character along a projection axisat a predetermined variable magnification, including a turret carrying aplurality of lenses of different effective focal length angularly spacedat equal radii on said turret and means mounting said turret forrotation such that said lenses are successively brought into position onsaid axis when said turret is rotated, said turret having a plurality ofsharply defined angularly spaced cam means;

motive means for rotating said turret unidirectionally at a constantrate;

electrically operable highly accurate locking means for locking saidturret upon actuation thereof;

position-sensing means for sensing the angular position of said turret,comprising:

a rotary switch coupled to and driven by said motive means fordetermining coarsely when a selected one of said plurality of lenses isapproaching said projection axis, and

switch means actuated by a cam follower positioned to sense said cammeans when said turret is rotated for determining when said lens issubstantially on said axis; and

control circuit means responsive to said rotary switch and to saidswitch means for actuating said locking means to lock said turret withsaid selected lens accurately positioned on said projection axis.

9. The apparatus defined by claim 8 wherein said cam means on saidturret comprise recesses in the periphery thereof, and wherein saidlocking means includes a solenoid having a plunger oriented to penetratea particular recess as sociated with said selected lens and thereby locksaid turret when said solenoid is energized by actuation of said lockingmeans.

10. The apparatus defined by claim 9 wherein said recesses have a femaleconical configuration and wherein said plunger has a tip with a maleconical configuration mating with said recesses.

11. In a photocomposing process, a method comprising: selecting acharacter to be recorded and locating said character on a projectionaxis; moving a series of lenses of difi'erent focal length successivelyacross said projection axis; electrically sensing coarsely when aselected one of said plurality of lenses is approaching said projectionaxis; electrically sensing more accurately when said selected lens issubstantially on said axis; and responsive to the said coarse and moreaccurate sensing,

locking said selected lens precisely on said axis.

1. In photocomposing apparatus, the combination comprising: means forestablishing a character to be recorded; a lens support carrying aplurality of lenses in spaced relationship; means mounting said lenssupport for movement such that said lenses are Successively brought intoposition on an optical projection axis when said support is moved; andlens support indexing means for moving said lens support to successivelylocate different ones of said plurality of lenses on said projectionaxis, comprising: motive means for moving said lens support, monitoringmeans for monitoring the position of said lens support to determinecoarsely when a selected one of said plurality of lenses is approachingsaid projection axis, electrical sensing means responsive to movement ofsaid lens support for determining when said selected lens is locatedsubstantially on said projection axis, electrically operable highlyaccurate mechanical locking means for locking said lens support, andcontrol means responsive to said monitoring means and to said sensingmeans for actuating said locking means when said selected lens issubstantially on said projection axis, said locking means upon actuationvery precisely fixing the position of said selected lens on said axis.2. In photocomposing apparatus, the combination comprising: means forestablishing a character to be recorded; a lens turret carrying aplurality of lenses in angularly spaced relationship; means mountingsaid turret for rotation such that said lenses are successively broughtinto position on an optical projection axis when said turret is rotated;and turret indexing means for rotating said turret to selectively locatedifferent ones of said plurality of lenses on said projection axis,comprising: motive means for rotating said turret, monitoring means formonitoring the angular position of said turret to determine coarselywhen a selected one of said plurality of lenses is approaching saidprojection axis, electrical sensing means responsive to movement of saidturret for determining when said selected lens is located substantiallyon said projection axis, electrically operable highly accuratemechanical locking means for locking said turret, said locking meansbeing positioned accurately with respect to said axis, and control meansresponsive to said monitoring means and to said sensing means foractuating said locking means when said selected lens is substantially onsaid projection axis, said locking means upon actuation very preciselyfixing the position of said selected lens on said axis.
 3. The apparatusdefined by claim 2 wherein said turret defines a plurality of recessesangularly spaced thereon and wherein said locking means includes asolenoid having a plunger adapted to enter one of said recesses to locksaid turret when said solenoid is energized.
 4. The apparatus defined byclaim 3 wherein each of said recesses has a female conical configurationand wherein said plunger has a tip with a male conical configurationmating with said female conical configuration of said recesses.
 5. Theapparatus defined by claim 2 wherein said turret includes a plurality ofsharply defined angularly spaced cam means, and wherein said sensingmeans comprises a switch having an actuator following said cam means. 6.The apparatus defined by claim 3 wherein said sensing means comprises aswitch having an actuator positioned to sense said recesses in saidturret.
 7. The apparatus defined by claim 6 wherein said monitoringmeans comprises a rotary switch operatively coupled to said motive meansand driven thereby in synchronism with said turret.
 8. In aphotocomposing machine, the combination comprising: means for displayinga character to be recorded; means for forming a real image of saidcharacter along a projection axis at a predetermined variablemagnification, including a turret carrying a plurality of lenses ofdifferent effective focal length angularly spaced at equal radii on saidturret and means mounting said turret for rotation such that said lensesare successively brought into position on said axis when said turret isrotated, said turret having a plurality of shaRply defined angularlyspaced cam means; motive means for rotating said turret unidirectionallyat a constant rate; electrically operable highly accurate locking meansfor locking said turret upon actuation thereof; position-sensing meansfor sensing the angular position of said turret, comprising: a rotaryswitch coupled to and driven by said motive means for determiningcoarsely when a selected one of said plurality of lenses is approachingsaid projection axis, and switch means actuated by a cam followerpositioned to sense said cam means when said turret is rotated fordetermining when said lens is substantially on said axis; and controlcircuit means responsive to said rotary switch and to said switch meansfor actuating said locking means to lock said turret with said selectedlens accurately positioned on said projection axis.
 9. The apparatusdefined by claim 8 wherein said cam means on said turret compriserecesses in the periphery thereof, and wherein said locking meansincludes a solenoid having a plunger oriented to penetrate a particularrecess associated with said selected lens and thereby lock said turretwhen said solenoid is energized by actuation of said locking means. 10.The apparatus defined by claim 9 wherein said recesses have a femaleconical configuration and wherein said plunger has a tip with a maleconical configuration mating with said recesses.
 11. In a photocomposingprocess, a method comprising: selecting a character to be recorded andlocating said character on a projection axis; moving a series of lensesof different focal length successively across said projection axis;electrically sensing coarsely when a selected one of said plurality oflenses is approaching said projection axis; electrically sensing moreaccurately when said selected lens is substantially on said axis; andresponsive to the said coarse and more accurate sensing, locking saidselected lens precisely on said axis.